Exercise: what’s that?

Before starting to discuss how exercise affects the physiology of animals, let’s look at how different scientists have tried to define exercise.

One of the definitions proposed by B. J. Whipp is:

"Exercise is a process which depends upon the transformation of the biochemical energy of ingested food into mechanical energy of muscle contraction and work."

Another definition of exercise proposed by D.R. Jones & D. J. Randall is:

"Exercise is work performed on the environment by the locomotory  muscles."

The two definitions highlight different aspects of what exercise is. In the first definition the conversion of food into biochemical energy is the focus whereas in the second it is the muscle work that is the focus.  Both definitions describe the same thing but from two different angles: fish (as is true of all animals) need energy to be able to move; in some way, the energy – coming from food – has to be converted to mechanical movements performed by the muscles.

 

What does Newton have to say about exercise, read more about it